Evaluation of controlled‐release devices for providing chromium sesquioxide and zinc in Huacaya alpacas at pasture

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Judson, GJ; McGregor, BA; Ellis, Keith; Howse, AM


Journal Article

Australian Veterinary Journal



458 - 463

Objectives To assess the effectiveness of controlled release device (CRD) for providing zinc and for estimating faecal output in alpacas and sheep at pasture. Methods Ten alpacas and ten sheep at pasture were paired within species and allocated at random to receive by mouth either one CRD containing chromium sesquioxide designed to function for about three weeks or two CRDs, one containing chromium sesquioxide and the other zinc oxide designed to release over a nominal 60 day period. Faecal concentrations of chromium, zinc and ash, blood and plasma concentrations of zinc and plasma activities of alkaline phosphatase were measured over a period of 117 days after treatment. Results The mean faecal chromium excretion profiles suggest that the CRDs performed in a similar manner in both species, the expiry date being nearly 30 days in alpacas and slightly more than 30 days in sheep. Using a common predetermined release rate of chromium from the CRDS the daily faecal outputs of alpacas and sheep were estimated to be 0.54 kg DM and 0.33 kg DM respectively. The CRD containing zinc oxide provided after one week an estimated daily release rate of 40 mg zinc with a lifetime of between 60 and 70 days in both species. The additional zinc did not elicit a response in blood zinc concentrations or in plasma alkaline phosphatase activities. Conclusion The CRDs were retained in the alimentary tract of alpacas and sheep, and both types functioned as predicted. The CRD delivering chromium sesquioxide at a known release rate provided an estimate of faecal dry matter output over a period of almost three weeks and the CRD formulated to deliver supplementary zinc at a specified release rate over a period of about eight weeks in both species.

Wiley Publishing Asia Pty Ltd

controlled release device; zinc; chromium sesquioxide, alpaca, sheep

Animal Management


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Journal article - Refereed


Judson, GJ; McGregor, BA; Ellis, Keith; Howse, AM. Evaluation of controlled‐release devices for providing chromium sesquioxide and zinc in Huacaya alpacas at pasture. Australian Veterinary Journal. 2018; 96(11):458 - 463. https://doi.org/10.1111/avj.12759

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